aboutsummaryrefslogtreecommitdiff
path: root/src/xz/coder.c
blob: 027d7d2fa2b7fd62eb9a67f16b010591d3b8a70d (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
///////////////////////////////////////////////////////////////////////////////
//
/// \file       coder.c
/// \brief      Compresses or uncompresses a file
//
//  Author:     Lasse Collin
//
//  This file has been put into the public domain.
//  You can do whatever you want with this file.
//
///////////////////////////////////////////////////////////////////////////////

#include "private.h"


/// Return value type for coder_init().
enum coder_init_ret {
	CODER_INIT_NORMAL,
	CODER_INIT_PASSTHRU,
	CODER_INIT_ERROR,
};


enum operation_mode opt_mode = MODE_COMPRESS;
enum format_type opt_format = FORMAT_AUTO;
bool opt_auto_adjust = true;
bool opt_single_stream = false;
uint64_t opt_block_size = 0;
uint64_t *opt_block_list = NULL;


/// Stream used to communicate with liblzma
static lzma_stream strm = LZMA_STREAM_INIT;

/// Filters needed for all encoding all formats, and also decoding in raw data
static lzma_filter filters[LZMA_FILTERS_MAX + 1];

/// Input and output buffers
static io_buf in_buf;
static io_buf out_buf;

/// Number of filters. Zero indicates that we are using a preset.
static uint32_t filters_count = 0;

/// Number of the preset (0-9)
static uint32_t preset_number = LZMA_PRESET_DEFAULT;

/// Integrity check type
static lzma_check check;

/// This becomes false if the --check=CHECK option is used.
static bool check_default = true;

#ifdef MYTHREAD_ENABLED
static lzma_mt mt_options = {
	.flags = 0,
	.timeout = 300,
	.filters = filters,
};
#endif


extern void
coder_set_check(lzma_check new_check)
{
	check = new_check;
	check_default = false;
	return;
}


static void
forget_filter_chain(void)
{
	// Setting a preset makes us forget a possibly defined custom
	// filter chain.
	while (filters_count > 0) {
		--filters_count;
		free(filters[filters_count].options);
		filters[filters_count].options = NULL;
	}

	return;
}


extern void
coder_set_preset(uint32_t new_preset)
{
	preset_number &= ~LZMA_PRESET_LEVEL_MASK;
	preset_number |= new_preset;
	forget_filter_chain();
	return;
}


extern void
coder_set_extreme(void)
{
	preset_number |= LZMA_PRESET_EXTREME;
	forget_filter_chain();
	return;
}


extern void
coder_add_filter(lzma_vli id, void *options)
{
	if (filters_count == LZMA_FILTERS_MAX)
		message_fatal(_("Maximum number of filters is four"));

	filters[filters_count].id = id;
	filters[filters_count].options = options;
	++filters_count;

	// Setting a custom filter chain makes us forget the preset options.
	// This makes a difference if one specifies e.g. "xz -9 --lzma2 -e"
	// where the custom filter chain resets the preset level back to
	// the default 6, making the example equivalent to "xz -6e".
	preset_number = LZMA_PRESET_DEFAULT;

	return;
}


static void lzma_attribute((__noreturn__))
memlimit_too_small(uint64_t memory_usage)
{
	message(V_ERROR, _("Memory usage limit is too low for the given "
			"filter setup."));
	message_mem_needed(V_ERROR, memory_usage);
	tuklib_exit(E_ERROR, E_ERROR, false);
}


extern void
coder_set_compression_settings(void)
{
	// The default check type is CRC64, but fallback to CRC32
	// if CRC64 isn't supported by the copy of liblzma we are
	// using. CRC32 is always supported.
	if (check_default) {
		check = LZMA_CHECK_CRC64;
		if (!lzma_check_is_supported(check))
			check = LZMA_CHECK_CRC32;
	}

	// Options for LZMA1 or LZMA2 in case we are using a preset.
	static lzma_options_lzma opt_lzma;

	if (filters_count == 0) {
		// We are using a preset. This is not a good idea in raw mode
		// except when playing around with things. Different versions
		// of this software may use different options in presets, and
		// thus make uncompressing the raw data difficult.
		if (opt_format == FORMAT_RAW) {
			// The message is shown only if warnings are allowed
			// but the exit status isn't changed.
			message(V_WARNING, _("Using a preset in raw mode "
					"is discouraged."));
			message(V_WARNING, _("The exact options of the "
					"presets may vary between software "
					"versions."));
		}

		// Get the preset for LZMA1 or LZMA2.
		if (lzma_lzma_preset(&opt_lzma, preset_number))
			message_bug();

		// Use LZMA2 except with --format=lzma we use LZMA1.
		filters[0].id = opt_format == FORMAT_LZMA
				? LZMA_FILTER_LZMA1 : LZMA_FILTER_LZMA2;
		filters[0].options = &opt_lzma;
		filters_count = 1;
	}

	// Terminate the filter options array.
	filters[filters_count].id = LZMA_VLI_UNKNOWN;

	// If we are using the .lzma format, allow exactly one filter
	// which has to be LZMA1.
	if (opt_format == FORMAT_LZMA && (filters_count != 1
			|| filters[0].id != LZMA_FILTER_LZMA1))
		message_fatal(_("The .lzma format supports only "
				"the LZMA1 filter"));

	// If we are using the .xz format, make sure that there is no LZMA1
	// filter to prevent LZMA_PROG_ERROR.
	if (opt_format == FORMAT_XZ)
		for (size_t i = 0; i < filters_count; ++i)
			if (filters[i].id == LZMA_FILTER_LZMA1)
				message_fatal(_("LZMA1 cannot be used "
						"with the .xz format"));

	// Print the selected filter chain.
	message_filters_show(V_DEBUG, filters);

	// Get the memory usage. Note that if --format=raw was used,
	// we can be decompressing.
	const uint64_t memory_limit = hardware_memlimit_get(opt_mode);
	uint64_t memory_usage;
	if (opt_mode == MODE_COMPRESS) {
#ifdef MYTHREAD_ENABLED
		if (opt_format == FORMAT_XZ && hardware_threads_get() > 1) {
			mt_options.threads = hardware_threads_get();
			mt_options.block_size = opt_block_size;
			mt_options.check = check;
			memory_usage = lzma_stream_encoder_mt_memusage(
					&mt_options);
			if (memory_usage != UINT64_MAX)
				message(V_DEBUG, _("Using up to %" PRIu32
						" threads."),
						mt_options.threads);
		} else
#endif
		{
			memory_usage = lzma_raw_encoder_memusage(filters);
		}
	} else {
		memory_usage = lzma_raw_decoder_memusage(filters);
	}

	if (memory_usage == UINT64_MAX)
		message_fatal(_("Unsupported filter chain or filter options"));

	// Print memory usage info before possible dictionary
	// size auto-adjusting.
	message_mem_needed(V_DEBUG, memory_usage);
	if (opt_mode == MODE_COMPRESS) {
		const uint64_t decmem = lzma_raw_decoder_memusage(filters);
		if (decmem != UINT64_MAX)
			message(V_DEBUG, _("Decompression will need "
					"%s MiB of memory."), uint64_to_str(
						round_up_to_mib(decmem), 0));
	}

	if (memory_usage <= memory_limit)
		return;

	// If --no-adjust was used or we didn't find LZMA1 or
	// LZMA2 as the last filter, give an error immediately.
	// --format=raw implies --no-adjust.
	if (!opt_auto_adjust || opt_format == FORMAT_RAW)
		memlimit_too_small(memory_usage);

	assert(opt_mode == MODE_COMPRESS);

#ifdef MYTHREAD_ENABLED
	if (opt_format == FORMAT_XZ && mt_options.threads > 1) {
		// Try to reduce the number of threads before
		// adjusting the compression settings down.
		do {
			// FIXME? The real single-threaded mode has
			// lower memory usage, but it's not comparable
			// because it doesn't write the size info
			// into Block Headers.
			if (--mt_options.threads == 0)
				memlimit_too_small(memory_usage);

			memory_usage = lzma_stream_encoder_mt_memusage(
					&mt_options);
			if (memory_usage == UINT64_MAX)
				message_bug();

		} while (memory_usage > memory_limit);

		message(V_WARNING, _("Adjusted the number of threads "
			"from %s to %s to not exceed "
			"the memory usage limit of %s MiB"),
			uint64_to_str(hardware_threads_get(), 0),
			uint64_to_str(mt_options.threads, 1),
			uint64_to_str(round_up_to_mib(
				memory_limit), 2));
	}
#endif

	if (memory_usage <= memory_limit)
		return;

	// Look for the last filter if it is LZMA2 or LZMA1, so we can make
	// it use less RAM. With other filters we don't know what to do.
	size_t i = 0;
	while (filters[i].id != LZMA_FILTER_LZMA2
			&& filters[i].id != LZMA_FILTER_LZMA1) {
		if (filters[i].id == LZMA_VLI_UNKNOWN)
			memlimit_too_small(memory_usage);

		++i;
	}

	// Decrease the dictionary size until we meet the memory
	// usage limit. First round down to full mebibytes.
	lzma_options_lzma *opt = filters[i].options;
	const uint32_t orig_dict_size = opt->dict_size;
	opt->dict_size &= ~((UINT32_C(1) << 20) - 1);
	while (true) {
		// If it is below 1 MiB, auto-adjusting failed. We could be
		// more sophisticated and scale it down even more, but let's
		// see if many complain about this version.
		//
		// FIXME: Displays the scaled memory usage instead
		// of the original.
		if (opt->dict_size < (UINT32_C(1) << 20))
			memlimit_too_small(memory_usage);

		memory_usage = lzma_raw_encoder_memusage(filters);
		if (memory_usage == UINT64_MAX)
			message_bug();

		// Accept it if it is low enough.
		if (memory_usage <= memory_limit)
			break;

		// Otherwise 1 MiB down and try again. I hope this
		// isn't too slow method for cases where the original
		// dict_size is very big.
		opt->dict_size -= UINT32_C(1) << 20;
	}

	// Tell the user that we decreased the dictionary size.
	message(V_WARNING, _("Adjusted LZMA%c dictionary size "
			"from %s MiB to %s MiB to not exceed "
			"the memory usage limit of %s MiB"),
			filters[i].id == LZMA_FILTER_LZMA2
				? '2' : '1',
			uint64_to_str(orig_dict_size >> 20, 0),
			uint64_to_str(opt->dict_size >> 20, 1),
			uint64_to_str(round_up_to_mib(memory_limit), 2));

	return;
}


/// Return true if the data in in_buf seems to be in the .xz format.
static bool
is_format_xz(void)
{
	// Specify the magic as hex to be compatible with EBCDIC systems.
	static const uint8_t magic[6] = { 0xFD, 0x37, 0x7A, 0x58, 0x5A, 0x00 };
	return strm.avail_in >= sizeof(magic)
			&& memcmp(in_buf.u8, magic, sizeof(magic)) == 0;
}


/// Return true if the data in in_buf seems to be in the .lzma format.
static bool
is_format_lzma(void)
{
	// The .lzma header is 13 bytes.
	if (strm.avail_in < 13)
		return false;

	// Decode the LZMA1 properties.
	lzma_filter filter = { .id = LZMA_FILTER_LZMA1 };
	if (lzma_properties_decode(&filter, NULL, in_buf.u8, 5) != LZMA_OK)
		return false;

	// A hack to ditch tons of false positives: We allow only dictionary
	// sizes that are 2^n or 2^n + 2^(n-1) or UINT32_MAX. LZMA_Alone
	// created only files with 2^n, but accepts any dictionary size.
	// If someone complains, this will be reconsidered.
	lzma_options_lzma *opt = filter.options;
	const uint32_t dict_size = opt->dict_size;
	free(opt);

	if (dict_size != UINT32_MAX) {
		uint32_t d = dict_size - 1;
		d |= d >> 2;
		d |= d >> 3;
		d |= d >> 4;
		d |= d >> 8;
		d |= d >> 16;
		++d;
		if (d != dict_size || dict_size == 0)
			return false;
	}

	// Another hack to ditch false positives: Assume that if the
	// uncompressed size is known, it must be less than 256 GiB.
	// Again, if someone complains, this will be reconsidered.
	uint64_t uncompressed_size = 0;
	for (size_t i = 0; i < 8; ++i)
		uncompressed_size |= (uint64_t)(in_buf.u8[5 + i]) << (i * 8);

	if (uncompressed_size != UINT64_MAX
			&& uncompressed_size > (UINT64_C(1) << 38))
		return false;

	return true;
}


/// Detect the input file type (for now, this done only when decompressing),
/// and initialize an appropriate coder. Return value indicates if a normal
/// liblzma-based coder was initialized (CODER_INIT_NORMAL), if passthru
/// mode should be used (CODER_INIT_PASSTHRU), or if an error occurred
/// (CODER_INIT_ERROR).
static enum coder_init_ret
coder_init(file_pair *pair)
{
	lzma_ret ret = LZMA_PROG_ERROR;

	if (opt_mode == MODE_COMPRESS) {
		switch (opt_format) {
		case FORMAT_AUTO:
			// args.c ensures this.
			assert(0);
			break;

		case FORMAT_XZ:
#ifdef MYTHREAD_ENABLED
			if (hardware_threads_get() > 1)
				ret = lzma_stream_encoder_mt(
						&strm, &mt_options);
			else
#endif
				ret = lzma_stream_encoder(
						&strm, filters, check);
			break;

		case FORMAT_LZMA:
			ret = lzma_alone_encoder(&strm, filters[0].options);
			break;

		case FORMAT_RAW:
			ret = lzma_raw_encoder(&strm, filters);
			break;
		}
	} else {
		uint32_t flags = LZMA_TELL_UNSUPPORTED_CHECK;
		if (!opt_single_stream)
			flags |= LZMA_CONCATENATED;

		// We abuse FORMAT_AUTO to indicate unknown file format,
		// for which we may consider passthru mode.
		enum format_type init_format = FORMAT_AUTO;

		switch (opt_format) {
		case FORMAT_AUTO:
			if (is_format_xz())
				init_format = FORMAT_XZ;
			else if (is_format_lzma())
				init_format = FORMAT_LZMA;
			break;

		case FORMAT_XZ:
			if (is_format_xz())
				init_format = FORMAT_XZ;
			break;

		case FORMAT_LZMA:
			if (is_format_lzma())
				init_format = FORMAT_LZMA;
			break;

		case FORMAT_RAW:
			init_format = FORMAT_RAW;
			break;
		}

		switch (init_format) {
		case FORMAT_AUTO:
			// Unknown file format. If --decompress --stdout
			// --force have been given, then we copy the input
			// as is to stdout. Checking for MODE_DECOMPRESS
			// is needed, because we don't want to do use
			// passthru mode with --test.
			if (opt_mode == MODE_DECOMPRESS
					&& opt_stdout && opt_force)
				return CODER_INIT_PASSTHRU;

			ret = LZMA_FORMAT_ERROR;
			break;

		case FORMAT_XZ:
			ret = lzma_stream_decoder(&strm,
					hardware_memlimit_get(
						MODE_DECOMPRESS), flags);
			break;

		case FORMAT_LZMA:
			ret = lzma_alone_decoder(&strm,
					hardware_memlimit_get(
						MODE_DECOMPRESS));
			break;

		case FORMAT_RAW:
			// Memory usage has already been checked in
			// coder_set_compression_settings().
			ret = lzma_raw_decoder(&strm, filters);
			break;
		}

		// Try to decode the headers. This will catch too low
		// memory usage limit in case it happens in the first
		// Block of the first Stream, which is where it very
		// probably will happen if it is going to happen.
		if (ret == LZMA_OK && init_format != FORMAT_RAW) {
			strm.next_out = NULL;
			strm.avail_out = 0;
			ret = lzma_code(&strm, LZMA_RUN);
		}
	}

	if (ret != LZMA_OK) {
		message_error("%s: %s", pair->src_name, message_strm(ret));
		if (ret == LZMA_MEMLIMIT_ERROR)
			message_mem_needed(V_ERROR, lzma_memusage(&strm));

		return CODER_INIT_ERROR;
	}

	return CODER_INIT_NORMAL;
}


/// Resolve conflicts between opt_block_size and opt_block_list in single
/// threaded mode. We want to default to opt_block_list, except when it is
/// larger than opt_block_size. If this is the case for the current Block
/// at *list_pos, then we break into smaller Blocks. Otherwise advance
/// to the next Block in opt_block_list, and break apart if needed.
static void
split_block(uint64_t *block_remaining,
	    uint64_t *next_block_remaining,
	    size_t *list_pos)
{
	if (*next_block_remaining > 0) {
		// The Block at *list_pos has previously been split up.
		assert(hardware_threads_get() == 1);
		assert(opt_block_size > 0);
		assert(opt_block_list != NULL);

		if (*next_block_remaining > opt_block_size) {
			// We have to split the current Block at *list_pos
			// into another opt_block_size length Block.
			*block_remaining = opt_block_size;
		} else {
			// This is the last remaining split Block for the
			// Block at *list_pos.
			*block_remaining = *next_block_remaining;
		}

		*next_block_remaining -= *block_remaining;

	} else {
		// The Block at *list_pos has been finished. Go to the next
		// entry in the list. If the end of the list has been reached,
		// reuse the size of the last Block.
		if (opt_block_list[*list_pos + 1] != 0)
			++*list_pos;

		*block_remaining = opt_block_list[*list_pos];

		// If in single-threaded mode, split up the Block if needed.
		// This is not needed in multi-threaded mode because liblzma
		// will do this due to how threaded encoding works.
		if (hardware_threads_get() == 1 && opt_block_size > 0
				&& *block_remaining > opt_block_size) {
			*next_block_remaining
					= *block_remaining - opt_block_size;
			*block_remaining = opt_block_size;
		}
	}
}


/// Compress or decompress using liblzma.
static bool
coder_normal(file_pair *pair)
{
	// Encoder needs to know when we have given all the input to it.
	// The decoders need to know it too when we are using
	// LZMA_CONCATENATED. We need to check for src_eof here, because
	// the first input chunk has been already read if decompressing,
	// and that may have been the only chunk we will read.
	lzma_action action = pair->src_eof ? LZMA_FINISH : LZMA_RUN;

	lzma_ret ret;

	// Assume that something goes wrong.
	bool success = false;

	// block_remaining indicates how many input bytes to encode before
	// finishing the current .xz Block. The Block size is set with
	// --block-size=SIZE and --block-list. They have an effect only when
	// compressing to the .xz format. If block_remaining == UINT64_MAX,
	// only a single block is created.
	uint64_t block_remaining = UINT64_MAX;

	// next_block_remining for when we are in single-threaded mode and
	// the Block in --block-list is larger than the --block-size=SIZE.
	uint64_t next_block_remaining = 0;

	// Position in opt_block_list. Unused if --block-list wasn't used.
	size_t list_pos = 0;

	// Handle --block-size for single-threaded mode and the first step
	// of --block-list.
	if (opt_mode == MODE_COMPRESS && opt_format == FORMAT_XZ) {
		// --block-size doesn't do anything here in threaded mode,
		// because the threaded encoder will take care of splitting
		// to fixed-sized Blocks.
		if (hardware_threads_get() == 1 && opt_block_size > 0)
			block_remaining = opt_block_size;

		// If --block-list was used, start with the first size.
		//
		// For threaded case, --block-size specifies how big Blocks
		// the encoder needs to be prepared to create at maximum
		// and --block-list will simultaneously cause new Blocks
		// to be started at specified intervals. To keep things
		// logical, the same is done in single-threaded mode. The
		// output is still not identical because in single-threaded
		// mode the size info isn't written into Block Headers.
		if (opt_block_list != NULL) {
			if (block_remaining < opt_block_list[list_pos]) {
				assert(hardware_threads_get() == 1);
				next_block_remaining = opt_block_list[list_pos]
						- block_remaining;
			} else {
				block_remaining = opt_block_list[list_pos];
			}
		}
	}

	strm.next_out = out_buf.u8;
	strm.avail_out = IO_BUFFER_SIZE;

	while (!user_abort) {
		// Fill the input buffer if it is empty and we aren't
		// flushing or finishing.
		if (strm.avail_in == 0 && action == LZMA_RUN) {
			strm.next_in = in_buf.u8;
			strm.avail_in = io_read(pair, &in_buf,
					my_min(block_remaining,
						IO_BUFFER_SIZE));

			if (strm.avail_in == SIZE_MAX)
				break;

			if (pair->src_eof) {
				action = LZMA_FINISH;

			} else if (block_remaining != UINT64_MAX) {
				// Start a new Block after every
				// opt_block_size bytes of input.
				block_remaining -= strm.avail_in;
				if (block_remaining == 0)
					action = LZMA_FULL_BARRIER;
			}

			if (action == LZMA_RUN && flush_needed)
				action = LZMA_SYNC_FLUSH;
		}

		// Let liblzma do the actual work.
		ret = lzma_code(&strm, action);

		// Write out if the output buffer became full.
		if (strm.avail_out == 0) {
			if (opt_mode != MODE_TEST && io_write(pair, &out_buf,
					IO_BUFFER_SIZE - strm.avail_out))
				break;

			strm.next_out = out_buf.u8;
			strm.avail_out = IO_BUFFER_SIZE;
		}

		if (ret == LZMA_STREAM_END && (action == LZMA_SYNC_FLUSH
				|| action == LZMA_FULL_BARRIER)) {
			if (action == LZMA_SYNC_FLUSH) {
				// Flushing completed. Write the pending data
				// out immediatelly so that the reading side
				// can decompress everything compressed so far.
				if (io_write(pair, &out_buf, IO_BUFFER_SIZE
						- strm.avail_out))
					break;

				strm.next_out = out_buf.u8;
				strm.avail_out = IO_BUFFER_SIZE;

				// Set the time of the most recent flushing.
				mytime_set_flush_time();
			} else {
				// Start a new Block after LZMA_FULL_BARRIER.
				if (opt_block_list == NULL) {
					assert(hardware_threads_get() == 1);
					assert(opt_block_size > 0);
					block_remaining = opt_block_size;
				} else {
					split_block(&block_remaining,
							&next_block_remaining,
							&list_pos);
				}
			}

			// Start a new Block after LZMA_FULL_FLUSH or continue
			// the same block after LZMA_SYNC_FLUSH.
			action = LZMA_RUN;

		} else if (ret != LZMA_OK) {
			// Determine if the return value indicates that we
			// won't continue coding.
			const bool stop = ret != LZMA_NO_CHECK
					&& ret != LZMA_UNSUPPORTED_CHECK;

			if (stop) {
				// Write the remaining bytes even if something
				// went wrong, because that way the user gets
				// as much data as possible, which can be good
				// when trying to get at least some useful
				// data out of damaged files.
				if (opt_mode != MODE_TEST && io_write(pair,
						&out_buf, IO_BUFFER_SIZE
							- strm.avail_out))
					break;
			}

			if (ret == LZMA_STREAM_END) {
				if (opt_single_stream) {
					io_fix_src_pos(pair, strm.avail_in);
					success = true;
					break;
				}

				// Check that there is no trailing garbage.
				// This is needed for LZMA_Alone and raw
				// streams.
				if (strm.avail_in == 0 && !pair->src_eof) {
					// Try reading one more byte.
					// Hopefully we don't get any more
					// input, and thus pair->src_eof
					// becomes true.
					strm.avail_in = io_read(
							pair, &in_buf, 1);
					if (strm.avail_in == SIZE_MAX)
						break;

					assert(strm.avail_in == 0
							|| strm.avail_in == 1);
				}

				if (strm.avail_in == 0) {
					assert(pair->src_eof);
					success = true;
					break;
				}

				// We hadn't reached the end of the file.
				ret = LZMA_DATA_ERROR;
				assert(stop);
			}

			// If we get here and stop is true, something went
			// wrong and we print an error. Otherwise it's just
			// a warning and coding can continue.
			if (stop) {
				message_error("%s: %s", pair->src_name,
						message_strm(ret));
			} else {
				message_warning("%s: %s", pair->src_name,
						message_strm(ret));

				// When compressing, all possible errors set
				// stop to true.
				assert(opt_mode != MODE_COMPRESS);
			}

			if (ret == LZMA_MEMLIMIT_ERROR) {
				// Display how much memory it would have
				// actually needed.
				message_mem_needed(V_ERROR,
						lzma_memusage(&strm));
			}

			if (stop)
				break;
		}

		// Show progress information under certain conditions.
		message_progress_update();
	}

	return success;
}


/// Copy from input file to output file without processing the data in any
/// way. This is used only when trying to decompress unrecognized files
/// with --decompress --stdout --force, so the output is always stdout.
static bool
coder_passthru(file_pair *pair)
{
	while (strm.avail_in != 0) {
		if (user_abort)
			return false;

		if (io_write(pair, &in_buf, strm.avail_in))
			return false;

		strm.total_in += strm.avail_in;
		strm.total_out = strm.total_in;
		message_progress_update();

		strm.avail_in = io_read(pair, &in_buf, IO_BUFFER_SIZE);
		if (strm.avail_in == SIZE_MAX)
			return false;
	}

	return true;
}


extern void
coder_run(const char *filename)
{
	// Set and possibly print the filename for the progress message.
	message_filename(filename);

	// Try to open the input file.
	file_pair *pair = io_open_src(filename);
	if (pair == NULL)
		return;

	// Assume that something goes wrong.
	bool success = false;

	if (opt_mode == MODE_COMPRESS) {
		strm.next_in = NULL;
		strm.avail_in = 0;
	} else {
		// Read the first chunk of input data. This is needed
		// to detect the input file type.
		strm.next_in = in_buf.u8;
		strm.avail_in = io_read(pair, &in_buf, IO_BUFFER_SIZE);
	}

	if (strm.avail_in != SIZE_MAX) {
		// Initialize the coder. This will detect the file format
		// and, in decompression or testing mode, check the memory
		// usage of the first Block too. This way we don't try to
		// open the destination file if we see that coding wouldn't
		// work at all anyway. This also avoids deleting the old
		// "target" file if --force was used.
		const enum coder_init_ret init_ret = coder_init(pair);

		if (init_ret != CODER_INIT_ERROR && !user_abort) {
			// Don't open the destination file when --test
			// is used.
			if (opt_mode == MODE_TEST || !io_open_dest(pair)) {
				// Remember the current time. It is needed
				// for progress indicator and for timed
				// flushing.
				mytime_set_start_time();

				// Initialize the progress indicator.
				const uint64_t in_size
						= pair->src_st.st_size <= 0
						? 0 : pair->src_st.st_size;
				message_progress_start(&strm, in_size);

				// Do the actual coding or passthru.
				if (init_ret == CODER_INIT_NORMAL)
					success = coder_normal(pair);
				else
					success = coder_passthru(pair);

				message_progress_end(success);
			}
		}
	}

	// Close the file pair. It needs to know if coding was successful to
	// know if the source or target file should be unlinked.
	io_close(pair, success);

	return;
}


#ifndef NDEBUG
extern void
coder_free(void)
{
	lzma_end(&strm);
	return;
}
#endif